Home » RDBMS Server » Performance Tuning » very high redo space wait ratios on 10g
very high redo space wait ratios on 10g [message #259214] Tue, 14 August 2007 12:15 Go to next message
sumang24
Messages: 10
Registered: July 2005
Junior Member
I upgraded the db from 9i to 10g recently. These are the stats:

The redo space wait ratio on 9i : 0.6708
The redo space wait ratio on 10g : 1112.21

9i:
Size of redo log file = 10 MB
4 groups with 2 members each
size of redo buffer: 14.7 MB
Total System Global Area 1249391632 bytes
Fixed Size 455696 bytes
Variable Size 721420288 bytes
Database Buffers 512000000 bytes
Redo Buffers 15515648 bytes



10g:
Size of redo log file = 10 MB
4 groups with 2 members each
size of redo buffer: 30 MB

sho sga
Total System Global Area 4378853376 bytes
Fixed Size 2035792 bytes
Variable Size 822087600 bytes
Database Buffers 3523215360 bytes
Redo Buffers 31514624 bytes

Do you think that the increased size of redo buffer ( almost double) on 10g is a contributing factor to high redo space
wait ratios. I have set the log_buffer to 14.6 MB in the spfile but because of
the granule size it shows at 30 MB on the v$sga view. I don't have any control
on the buffer size.


Thank You
Re: very high redo space wait ratios on 10g [message #259220 is a reply to message #259214] Tue, 14 August 2007 12:43 Go to previous messageGo to next message
Michel Cadot
Messages: 64152
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Your redo files are far too small, check switch frequency and enlarge them.

Regards
Michel
Re: very high redo space wait ratios on 10g [message #259392 is a reply to message #259214] Wed, 15 August 2007 08:36 Go to previous message
orafaqer
Messages: 48
Registered: July 2006
Member
And the log_buffer is too large. But it's not an issue, just useless memory consumption.
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